Power operated rotary knives are widely used in meat processing facilities for meat cutting and trimming operations. Such power operated rotary knives typically include a handle assembly including a head member extending from the handle assembly, an annular blade housing coupled to the head member via a clamp assembly, and an annular rotary blade supported for rotation by the blade housing. The annular rotary blade of a conventional power operated rotary is rotated by a drive mechanism including a flexible drive shaft which extends through an opening in the handle assembly and engages a pinion gear supported in a distal portion of the handle assembly head member. The flexible drive shaft includes a stationary outer sheath and a rotatable interior drive shaft which is driven by a pneumatic or electric motor. Gear teeth of the pinion gear engage mating gear teeth formed on an upper surface of the annular rotary blade. Upon rotation of the pinion gear by the flexible drive shaft, the annular rotary blade rotates within the blade housing at a high RPM, on the order of 1,500-2,000 RPMs. Conventional power operated rotary knives are disclosed in U.S. Pat. No. 6,354,949 to Baris et al., U.S. Pat. No. 6,751,872 to Whited et al., U.S. Pat. No. 6,769,184 to Whited, and U.S. Pat. No. 6,978,548 to Whited et al., all of which are assigned to the assignee of the present invention and all of which are incorporated herein in their respective entireties by reference.
Due to advances in biomedical technology, tissue engineering and the ability to safely sterilize musculoskeletal tissue, there is an increasing demand for more donated human tissue. Musculoskeletal, cardio-vascular, eye and skin/dermis are tissues commonly recovered for transplantation. Tissue processing agencies typically receive the tissue after legal consent is obtained under the Uniform Anatomical Gift Act (UAGA) and adopted state revisions from Food and Drug Administration (FDA) and the American Association of Tissue Banks (AATB) approved procurement agencies. After a comprehensive screening process, the tissue may be used for transplantation purposes, medical research and/or medical education. Long bone of the human body, e.g., femurs are especially valuable due to their thicker cortical walls and therefore the ability to be manufactured into weight bearing spinal constructs. In some instances, bone marrow may also be extracted in order to create stem cell infused bone products which promote incorporation and healing. In many instances, soft tissues of the lower extremities may also be recovered for transplantation purposes such as the gracilis, semitendinosus, achilles and knee tendons. Requirements for successfully recovering human donor bones are stringent, both in terms of the very limited time period after death in which bones can be successfully recovered after death of the donor (typically, within 24 hours after death) and in terms of conditions of sterility required during the bone harvesting process. The sterility required for harvesting of human donor body parts is akin to the sterility required during human surgery.
Under the AATB guidelines, human bone must be recovered within 24 hours of the documented time of death if the body is refrigerated and within 15 hours of the documented time of death if the body is not refrigerated. Under established rules, if a death occurs in a hospital, the decedent must be referred for evaluation of organ/tissue donation to the hospital's designated Organ Procurement Organization (OPO). The OPO may have their own tissue recovery team or may elect to refer to a contracted tissue and eye recovery agency for medical suitability evaluation. If the donor is medically cleared for donation, tissue is recovered by trained technicians in a clean environment utilizing sterile disposable drapes and instrumentation. The tissue is generally recovered in “zone” or, at the location of the donor, cultured and individually placed in disposable sterile bags and stored on wet ice in validated shipping containers prior to shipment to a tissue processor.
Once the shipping container is received at a musculoskeletal tissue processing facility, the tissue is monitored for temperature and inventoried. Typically, the tissue is cultured, re-bagged and stored in freezers until serological, microbiological and fungal test results are completed. Additionally, a full medical record review, to include the donor's medical/social history and post-mortem exam, if applicable, are reviewed by a medical doctor before the tissue is released for processing. Upon release, the tissue is thawed and moved to technicians who engage in debriding the bone. Debriding is the process that involves removing tissue such as muscle, ligaments, tendons, adipose and other tissue from the recovered bone. After debriding the bones, the recovered, debrided bones are placed in a container having a low temperature interior region to preserve the recovered bones placed in the container. Generally, no gross debridement with power tools is performed by recovery teams in the field. Processors prefer leg en-bloc recovery to prevent recovery team technicians from damaging tendons and meniscus. Gross debridement is performed by a separated technical team in a controlled environment at the musculoskeletal tissue processing facility, e.g., AlloSource, Regeneration Technologies, Inc. or Musculoskeletal Transplant Foundation.
With regard to recovery of full thickness skin or dermis, the removal of the upper dermal layer and fat is required prior to processing. This is also referred to as debriding tissue. Such an upper layer of skin tissue from the donor's abdomen and buttocks areas may be used as, for example, a cover or dressing for severely burned areas of a burn patient.
Typical instruments used for removing or debriding tissue from recovered bones include scalpels, stainless steel medical chisels, and power operated tools having disposable, stainless steel brushes wherein the brush bristles scour away tissue from the surface of the recovered bones. Additionally, a liquid may be applied to a recovered bone to soften attached tissue prior to debriding. Unfortunately, use of all of scalpels, chisels and power operated brushes is slow, time consuming and tedious. The tissue debriding process may include multiple steps: first larger pieces of tissue adhering to a recovered bone may be removed with a chisel; remaining smaller pieces of tissue may be cut away with a scalpel; finally, remaining tissue may be scoured away with a power operated brush.
Further, since insuring sterility in the recovery process and avoiding the possibility cross contamination between donors is of paramount importance, the instruments used for tissue debriding must be sterilized prior to use and either: 1) disposable upon completion of the harvesting process for a given donor; or 2) capable of being autoclaved, that is, sterilized after use.
Utilizing power operated rotary knives would appear to have potential for use in various tissue removal and/or tissue recovery operations including, for example, debriding bones, debriding full thickness skin, recovery of tendons and ligaments, among others. However, the sterility requirements of the human donor recovery process raise issues and create problems that have effectively precluded the use of conventional power operated rotary knives in human donor recovery. The number of individual components of a conventional power operated rotary knife is large and the assembly/disassembly process is time-consuming. Thus, the time and cost to disassemble and sterilize all of the components of a conventional power operated rotary knife and then reassemble the knife under sterile conditions prior to use on a new donor would be problematic. Additionally, disposability of, for example, the annular rotary blade is not feasible economically, that is, the annular rotary blade of a conventional power operated rotary knife is simply too expensive to be discarded after use of the blade for a relatively short time on a single donor. When used in meat processing facilities, a typical annular rotary blade is resharpened numerous times and, when properly maintained, may be used for an extended period of time in the range of 50-100 hours or more, prior to being discarded.
What is needed is a power operated rotary knife that may be effectively used for tissue removal or tissue debriding in the recovery of human donor body parts, including, but not limited to bone debriding, full thickness skin debriding, and/or tendon/ligament recovery operations/processes. What is also needed is a power operated rotary knife that is cost effective for use in recovery of human donor body parts, including, but not limited to, tissue removal or debriding such as bone debriding, full thickness skin debriding, tendon/ligament harvesting operations/processes. What is also needed is a power operated rotary knife that would provide a reduced number of components, ease of sterilization of reusable components, and/or disposable components/assemblies. What is also needed is a power operated rotary knife that is easy to assembly and dissemble for sterilization purposes and/or replacement of disposable components/assemblies.
It should also be recognized, of course, that the foregoing is equally applicable to non-human donors. For example, certain animals, such as pigs, have body parts that may be useful to human patients and are, therefore, recovered for medical purposes. Thus, to the extent that tissue recovery operations such as debriding of bones, debriding of skin, tendon/ligament harvesting operations/processes are carried out on non-human donors, the method and apparatus of the present disclosure is equally applicable to and is intended to cover such non-human donors and associated recovery/harvesting operations/processes.